Using a kitchen scale, weigh out 8.48 oz coconut oil in a stainless steel pot. In a bowl, measure 12.48 oz olive oil. In a second bowl, measure 7.9 oz coffee. Measure 3.22 oz lye in a third bowl. Measure out 1 tablespoon coffee grounds and 1/3 cup oat brain in a fourth bowl; set aside.

Put on protective gear, and make sure you are in a well-ventilated area. Add the lye to the coffee, and stir to dissolve. (Always add lye to liquid, not the other way around.) This will start a chemical reaction, and the mixture will get quite hot. Set aside. You may remove eyewear and face mask at this point, but gloves should remain on.

3. Emulsify

Melt coconut oil over low heat until no solids remain. Add olive oil. Using a stainless steel thermometer, check the temperature of the oils. Compare against the temperature of the lye solution, and adjust until they’re within a degree or two or each other, between 100 and 110 degrees.

Pour the lye solution into the oils, and use a hand or stick blender to emulsify until the mixture begins to thicken and the texture resembles pudding. This process will take 5 to 10 minutes with a stick blender and up to an hour with a hand blender. Once the soap has thickened, stir in the coffee grounds and oat bran with the stainless steel spoon or spatula.

4. Pour + Let Sit

Slowly pour the mixture into a soap mold. Lift and tap the mold against the counter a few times to release air bubbles. Cover with parchment paper, and then wrap the entire mold with a towel to insulate it.

5. Cut Bars

After 24 to 48 hours, remove the towel, and take the soap out of the mold. Let the soap loaf sit for another day to harden further before cutting into bars. Any sharp knife will work here. A vegetable peeler can be used to smooth sides, if desired.

6. Cure

After the soap is cut into bars, you’ll need to let them cure in a cool and well-ventilated area for four weeks. This allows the soap to finish saponification and for all the excess water to evaporate. Before you know it you will be able to enjoy your soap!